1. Field of the Invention
The present invention relates to hydraulic steering systems and, in particular, to power assisted hydraulic steering systems for marine vessels and other vehicles.
2. Description of the Related Art
Conventional power assisted hydraulic steering systems for marine vessels generally comprise a hydraulic circuit including a helm, a power assist hydraulic pump, and a hydraulic actuator. Hydraulic lines connect the helm to the hydraulic actuator which, in turn, is connected to a rudder. The helm is provided with a hydraulic helm pump which supplies fluid to the hydraulic actuator. The helm is operated by manual rotation of a steering wheel. The power assist hydraulic pump is typically actuated by an engine driven pump or an on-board electric motor which is running any time the ignition or engines are on. Additionally, the power assist hydraulic pump is generally sized to provide full assist at engine idle which results in increased energy expenditure and accelerated system wear.